from the North and the South, the Bulgarian High Command divided the Second Army in two operational groups. The Northern Group was to operate along the valley of the river Morava and in the direction of the Kosovo plain while the Southern Group had to advance along the Vardar against the French and British. The army was deemed too weak for these tasks and had to be reinforced by the 11th Macedonian Infantry Division, the 5th Danube Infantry Division that joined it by the middle of October and latter with the 2nd Thracian Infantry Division. This allowed the Northern Group to repel several Serbian attacks against Gnjilane and Kačanik in the south the Bulgarians waited for reinforcements and fought several battles with the French around Krivolak and the British south of Strumitsa. With the fall of Niš to the north the first phase of the campaign against Serbia ended and the second and last began. The Central Powers decided to attempt an encirclement of the Serbian Army at the Kosovo Pole. The Second Army was to take part with its Northern Operations Group while it remained on the defensive in the south. The operation lasted for several weeks and on 10 November (23 November) Pristina fell. The attempted encirclement however failed and part of the Serbian Army managed to withdraw through Albania to the Adriatic coast due to the slow advance from the north which allowed them to concentrate bigger forces against the Bulgarian Second Army and considerably reduce its speed. The Central Powers were content only with pursuing them with parts of the Second Army and the Austro-Hungarian 3rd Army. On 17 November Prizren was taken but all contact between the Bulgarian and Serbian forces was lost. Gradually the rest of western Macedonia was occupied and by December the Bulgarians entered Monastri where the Serbian Campaign ended. After the fall of Pristina and Prizren the Bulgarian High Command again turned its attention to the south and began transferring reinforcements for operations against the Entente forces that had grown to as much as 130,000 men. General Maurice Sarrail realized that the defeat of the Serbian Army made his positions untenable in the face of the whole Bulgarian First and Second armies and began to withdraw parts of his army. By December the Bulgarian Second Army undertook a major offensive against the retreating allies and after several engagements with the French